The design of a building has a profound impact on the light levels throughout the building. For example, the amount and location of windows as well as the orientation of the building with respect to the path of the sun can vastly affect the amount of light that enters a particular room. Other design aspects can also affect a room, such as the color and type of paint chosen for the walls, the arrangement and finishes of furniture, and the placement of internal lighting fixtures, to name a few. Daylight levels that are too high can cause glare and discomfort to those occupying the building, while daylight levels that are too low can increase energy costs for artificial lighting.
In order to take lighting conditions into account during the design phase, CAD tools are needed to be able to accurately simulate light transport through the building. These tools may analyze a building model taking into consideration such aspects of structure design, building materials, and the date and time of day. Many conventional tools are configured to perform full lighting simulations to provide some insight into the levels of illumination associated with a given design. However, the complexity of light transport simulation makes it hard to identify and study how and why certain design decisions change the levels of illumination. For example, while conventional tools may use ray-tracing techniques in order to generate an image of a portion of the model with simulated lighting conditions, the conventional tools may not be good at separating the effects between the color of a floor and the color of a paint used for the wall. Instead, a user must run different simulations, generating different images for each combination of materials and then compare the images in order to determine the effects from any one particular combination of design choices. Such techniques are tedious and reduce the efficiency of the architect when designing buildings or other structures. Thus, there is a need for addressing these issues and/or other issues associated with the prior art.